In this nozzle, unlike U.S. Pat. No. 4,994,660, published on 2.19.91, only a part of the divergent zone of the nozzle is oriented, downstream of the throat area A8, and it has the advantage of simplifying sealing between the two zones mentioned, in accordance with Spanish Patent No. 9200369, of Feb. 20, 1992.
Nevertheless, there is a problem of sealing between divergent main petals during the orientation of the flow. There are various solutions for solving the sealing of gaps between divergent main petals, such as those mentioned in U.S. Pat. No. 4,690,330, published on Sep. 1 1987, U.S. Pat. No. 4,662,566, published on May. 5, 1987. U.S. Pat. No. 5,039,014, published on Aug. 13 1991 and U.S. Pat. No. 5,076,496, published on Dec. 31, 1991, and in Spanish Patent and Patent Applications No. 9200369, of 1992, No. 9202157, of 1992, and No. 9301991, of 1993.
Moreover, Spanish Patent Application No. 9301515, of 1993, mentions the embodiment of a peripheral mechanism for regulating the throat area A8, which consists, unlike the peripheral mechanism in U.S. Pat. No. 3,760,436, published on May. 1, 1973, of an assembly of only one link rod, a crank having only two arms and one link rod bar for each convergent main petal.
Spanish Patent No. 9200369, of 1992, claims an orientable axisymmetric nozzle of variable geometry for gas turbine engines. The nozzle consists of a convergent zone and a divergent zone, both formed by main petals and secondary petals distributed circumferentially about the longitudinal axis of the engine, and which includes means of control and external radial support, for regulating the throat area, and means of control for orientation of the flow, being defined in that the regulating of the throat area A8 and the orientation of the flow are achieved by means of a single control system.
This single control system consists, in one of the embodiments, in combination, of two rings, each having a single body, called the internal and intermediate half-rings and of two double-jointed half-rings, called external ring segments the components of said combination of rings being mutually concentric and concentric with the longitudinal axis of the engine, and of a mechanism for regulating the throat area, and of a plurality of control actuators articulated by their upstream end to the fixed structure of the engine.
In the one embodiment, the internal and the intermediate rings and the external ring segments are mutually connected by two pairs of spindles, one pair perpendicular to the other pair, and one of the pair of spindles connecting the intermediate ring to the internal rind, and the other pair of spindles connecting the intermediate ring to the articulated ends of the external ring segments, in which the regulating of the throat area is achieved by axial displacement of the assembly of rings and external ring segments, and in which the variation of the outlet area with respect to an immobilized throat area is achieved by a simultaneous and opposite direction tilting of the two external ring segments, and in which the thrust segments, and in which the thrust vectoring is achieved by a simultaneous and same direction tilting of the two external ring segments with the centers of tilting on the longitudinal axis of the engine.
The convergent main petals are connected at their upstream end to the internal ring, by cylindrical articulations tangential to a theoretical circumference concentric with the longitudinal axis of the engine and located in a theoretical plane perpendicular to said longitudinal axis of the engine. The external ring segments and the pair of spindles which interarticulates them; are joined, for their part, by of ball-and-socket joints, to the downstream end of the above-mentioned control actuators.
The mechanism for regulating the throat area A8, in one of the embodiments mentioned in said Spanish Pat. No. 9200369, of 1992, consists, for each convergent main petal, of a link rod articulated to the fixed structure of the engine and to said convergent main petal.
The upstream end of each divergent main petal is joined to the downstream end of the corresponding convergent main petal by a cylindrical articulation, tangential to a theoretical circumference concentric with longitudinal axis of the engine and located in a theoretical plane perpendicular to said longitudinal axis of the engine.
Each main petal of the divergent zone is subdivided transversely into two segments which are connected together by and the of a cylindrical articulation having the axis perpendicular to the axis of the said articulation between this divergent main petal and its upstream convergent main petal, the downstream segments in said Spanish Patent No. 9200369 being connected to the corresponding external ring segment by a bar which is joined to said segment by a ball-and-socket joint, and to the corresponding external segment ring, a third cylindrical articulation, tangential to a theoretical circumference concentric with the longitudinal axis of the engine and located in a theoretical plane perpendicular to said longitudinal axis of the engine.
Spanish Patent Application No. 9202157, of 1992, describes and claims a design for a divergent secondary petal for sealing the longitudinal gap between contiguous divergent main petals. The geometry of said longitudinal gaps between divergent main petals alters during the orientation of the flow, changing from an approximately rectangular form to that of a regulated surface whose sides are no longer parallel.
Said Spanish Patent Application No. 9202157 proposes converting every divergent secondary petal into a deformable structural assembly with minimal torsional rigidity, composed of a base plate and of a plurality of discrete transverse elements inserted into said base plate. This base plate gives the assembly axial rigidity, acting as an element bearing the axial forces due to the flow of gas the cooling air and the inertia forces, exhibiting, however, minimum capacity for transmitting transverse and torsional forces. For their part, the discrete transverse elements lack the capacity to transmit torsional forces, and transmit the transverse and shear forces imposed both by the flow of gas and by the divergent main petals to which is transmitted the pressure of gas exerted on the base plate bearing the axial forces.
In this manner, Spanish Patent No. 9200369 and Spanish Patent Application No. 9202157, of 1992, offer a mechanism capable of orienting the flow of gas acting solely on one part of the divergent zone of the nozzle and of adequate sealing of the transverse gap between zones and of the longitudinal gaps between contiguous divergent main petals. Spanish Patent Application No. 9301991, of 1993, describes and claims a divergent main petal which makes it possible to increase the maximum angle of orientation of the flow with respect to that which it is possible to achieve with the embodiments mentioned in Spanish Patent No. 9200369 and in Spanish Patent Application No. 9202157.
Upon orienting a part of the divergent zone of the nozzle, the divergent main petals, as described in Spanish Patent No. 9200369, are forced to move in the radial direction and their downstream segment in the tangential direction with respect to the longitudinal axis of the engine, the maximum angle of orientation of said part of the divergent zone for a given throat area A8 being limited by the interference between main and secondary petals in zones close to the outlet area A9. As indicated above, Spanish Patent Application No. 9202157, of 1992, proposes converting the divergent secondary petal into a deformable structural assembly with minimal torsional rigidity, composed of a base plate bearing the axial forces and with minimum capacity for transmitting the transverse forces and discrete transverse elements with the capacity to transmit the transverse and shear forces imposed both by the flow of gas and by the divergent main petals. If the inner surface, in contact with the flow of gas, of the divergent main petals is planar, the maximum angle of orientation of the flow is determined by the interference in zones close to the outlet area A9 of said inner surface with the discrete transverse elements since, in this case, the longitudinal edges of the base plate do not bear on the inner surface of the divergent main petals, a longitudinal aperture appearing, which permits the gases to pass outside.
In order to solve the above problem, Spanish Patent Application No. 9301991 proposes a divergent main petal which has an inner surface, in contact with the flow of gases, of variable form between two transverse sections, one of them straight, coincident with or close to the upstream far transverse edge of the petal, and another curved, coincident with or close to the downstream far transverse edge of said petal, having the convexity facing towards the inside of the engine. The transition between both sections is achieved progressively and smoothly in order to permit continuous contact between the divergent secondary petal and said inner surface.
Spanish Patent Application No. 9302455, of 1993, describes and claims a divergent main petal and a novel system for connecting said petal to the corresponding external segment ring. Said connection system consists of two bars, a two hinged bar and an upstream intermediate bar, respectively, which are interlinked by a intermediate cylindrical articulation, the outer end of the two hinged bar is joined to the corresponding external ring by segment a cylindrical articulation, and the inner end of the upstream intermediate bar of is joined, by of a spherical knuckle, to the tangentially moveable downstream segment of the divergent main petal at an intermediate point, at the same time as said intermediate cylindrical articulation is connected to the downstream end of said downstream segment of said divergent main petal by another downstream intermediate bar, having a spherical knuckle in each end.
The invention presented in said Spanish Patent Application No. 9302455 results, during the orientation of the flow, in the tangential movement experienced by the downstream segment of the divergent main petal being defined solely by the two-hinged bar for connection to the corresponding external segment ring, and by the upstream intermediate bar, which, maintaining the connection point of the two-hinged bar and the two intermediate bars, and modifying the longitudinal position of the ball-and-socket joint which links the tangentially moveable downstream segment of the divergent main petal and the upstream intermediate bar, results in it being possible to regulate in the most convenient manner the tangential movement of the downstream segment of the divergent main petal to a fixed radial movement.
Moreover, Spanish Patent Application No. 9301515 mentions the embodiment of a peripheral mechanism for regulating the throat area A8 consisting, unlike the peripheral mechanism in U.S. Pat. No. 3,760,436, published on May. 1, 1973, of an assembly having only one link rod, a crank having only two arms and a two-hinged peripheral bar each for each convergent main petal, said link rod being linked, by a ball-and-socket joint, at its upstream end, to the intermediate ring which can be displaced axially without any tilting, and its downstream end to the crank, which is, in turn, joined to the convergent main petal corresponding to it by a cylindrical articulation having an axis perpendicular to the base of said convergent main petal, the ball-and-socket joint joining the link rod and the crank being at a point not located on the axis of said cylindrical articulation,